Setup remote debugging of manager while it's running in cluster (#74)

Dockerfile-debug

@@ -0,0 +1,29 @@
+# Build the manager binary
+FROM golang:1.16 as builder
+
+WORKDIR /workspace
+# Copy the Go Modules manifests
+COPY go.mod go.mod
+COPY go.sum go.sum
+# cache deps before building and copying source so that we don't need to re-download as much
+# and so that source changes don't invalidate our downloaded layer
+RUN go mod download
+
+RUN CGO_ENABLED=0 go get github.com/go-delve/delve/cmd/dlv
+
+# Copy the go source
+COPY . .
+
+# Build
+RUN --mount=type=cache,target=/root/.cache/go-build --mount=type=cache,target=/root/go/pkg CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -gcflags "all=-N -l" -v -o manager main.go
+
+# Use distroless as minimal base image to package the manager binary
+# Refer to https://github.com/GoogleContainerTools/distroless for more details
+FROM gcr.io/distroless/static:nonroot
+WORKDIR /
+COPY --from=builder /workspace/manager .
+COPY --from=builder /go/bin/dlv .
+USER 65532:65532
+
+ENTRYPOINT ["/dlv", "--listen=:40000", "--headless=true", "--api-version=2", "exec", "/manager"]
+

Makefile

@@ -1,6 +1,7 @@
 
 # Image URL to use all building/pushing image targets
 IMG ?= kusk-gateway:dev
+
 # Produce CRDs that work back to Kubernetes 1.11 (no version conversion)
 CRD_OPTIONS ?= "crd:trivialVersions=true,preserveUnknownFields=false"
 
@@ -73,6 +74,8 @@ run: install-local generate fmt vet ## Run a controller from your host, proxying
 docker-build: ## Build docker image with the manager.
 	DOCKER_BUILDKIT=1 docker build -t ${IMG} .
 
+docker-build-debug: ## Build docker image with the manager and debugger.
+	DOCKER_BUILDKIT=1 docker build -t "${IMG}-debug" -f ./Dockerfile-debug .
 docker-push: ## Push docker image with the manager.
 	docker push ${IMG}
 
@@ -94,6 +97,12 @@ deploy: manifests kustomize ## Deploy controller to the K8s cluster specified in
 	cd config/manager && $(KUSTOMIZE) edit set image controller=${IMG}
 	$(KUSTOMIZE) build config/default | kubectl apply -f -
 
+deploy-debug: manifests kustomize ## Deploy controller with debugger to the K8s cluster specified in ~/.kube/config.
+	cd config/manager && $(KUSTOMIZE) edit set image controller=${IMG}-debug
+	cd config/default && $(KUSTOMIZE) edit add patch --path ./manager_debug_patch.yaml
+	$(KUSTOMIZE) build config/default | kubectl apply -f -
+	cd config/default && $(KUSTOMIZE) edit remove patch --path ./manager_debug_patch.yaml
+
 undeploy: ## Undeploy controller from the K8s cluster specified in ~/.kube/config.
 	$(KUSTOMIZE) build config/default | kubectl delete -f -
 

README.md

@@ -93,3 +93,13 @@ curl -v -X GET 'http://localhost:8080/petstore/api/v3/pet/findByStatus?status=av
 ```
 
 For the convenience you can use provided petshop-openapi-short-with-kusk.yaml or petshop-openapi-short-with-kusk-and-mock.yaml files in ./development.
+
+# Remote debugging contoller-manager in cluster
+- Set up remote debugging for your IDE pointed at localhost:40000 
+  - [Goland](https://www.jetbrains.com/help/go/attach-to-running-go-processes-with-debugger.html#attach-to-a-process-in-the-docker-container)
+  - [VSCode](https://github.com/golang/vscode-go/blob/master/docs/debugging.md#configure)
+- Run `make create-env`
+- When the make script is waiting for kusk-controller-manager to become healthy, run `kubectl port-forward deployment/kusk-controller-manager -n kusk-system 40000:40000`
+- Run your debug configuration from your IDE. The pod won't become healthy until you do this as Delve waits for a connection on :40000.
+- When the script completes, you can now deploy httpbin with `kubectl apply -f examples/httpbin`
+- Place breakpoints in the code and debug as normal

config/default/manager_debug_patch.yaml

@@ -0,0 +1,31 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: controller-manager
+  namespace: system
+spec:
+  template:
+    spec:
+      containers:
+        - name: manager
+          resources: null
+          command:
+            - /dlv
+            - --listen=:40000
+            - --headless=true
+            - --api-version=2
+            - exec
+            - /manager
+            - --
+            - "--health-probe-bind-address=:8081"
+            - "--metrics-bind-address=127.0.0.1:8080"
+            - "--leader-elect"
+          args: []
+          securityContext:
+            capabilities:
+              add:
+                - SYS_PTRACE
+          ports:
+            - containerPort: 40000
+              name: debug
+              protocol: TCP

development/cluster/create-env.sh

@@ -51,7 +51,7 @@ echo "========> building control-plane docker image and installing into cluster"
 
 SHELL=/bin/bash
 eval $(minikube docker-env --profile "kgw")
-make docker-build deploy
+make docker-build-debug deploy-debug
 
 kubectl rollout status -w deployment/kusk-controller-manager -n kusk-system